Solution manual of CHemical principles in the laborary 7e

Instructor's Manual

Chemical Principles in the Laboratory
Eleventh Edition

Wayne C. Wolsey
Robert C. Rossi
Emil J. Slowinski

Macalester College
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TABLE OF CONTENTS
Page
Preface

1

List of Experiments

3

Equipment and Chemical Reagent Requirements
General Information

4-5

Experiments 1 – 43

6 - 50

Discussion of Experiments
Information for Laboratory Supervisors
Experiments 1 – 43

51
52 - 149

Suggested Procedures for Disposal of Reaction Products

150 - 160

Directions for Preparing Solutions

161 – 168

© 2016 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.


1
INSTRUCTORS' GUIDE FOR
CHEMICAL PRINCIPLES IN THE LABORATORY, 11TH EDITION
PREFACE
The adoption of a different laboratory manual always involves a certain amount of work on the part of
the stockroom personnel and the laboratory supervisor at the institution, since there will inevitably be
some new equipment which is required and different reagent solutions which must be prepared. The
purpose of this guide is to make the transition to "Chemical Principles in the Laboratory" as easy as
possible, and to assist in the matter of having the laboratory session work smoothly and productively.
To this end we have divided the guide into two rather distinct parts. In the first part we have listed the
equipment and chemical needs for each of the experiments. The equipment specified is that not already

included in the recommended student equipment listed in Appendix VI of the lab manual. The amounts
given are those we have found necessary, or convenient, for handling one laboratory section of 20
students. Since most courses in general chemistry will be larger than this, some much larger, we also
have listed in parentheses after each reagent an estimate of the amount of that reagent that would be used
by one student. Since reagent solutions and chemicals must be prepared somewhat in advance of the
laboratory sessions, these estimates should serve at least as an initial rough guide as to requirements for
the entire group of students who will be performing the experiment. Amounts actually used will
obviously vary, depending on conditions, and your experience with a given experiment will give you a
better estimate. In some cases the cost of the chemicals required may be very significant, and we have
kept the amounts used in such instances to a practical minimum. Directions for the preparation of all
reagent solutions used in the experiments are given at the end of this guide.
Since the expense involved in performing a laboratory experiment varies considerably, we have included
an estimate of the cost per student, based on 2007 prices, with each experiment. Most experiments cost
about 50¢ per student, for a total of roughly $8 per student per semester, exclusive of the cost of
recoverable metals and chemicals. In some of the experiments we call for equipment that may not be
immediately available. For the most part, this equipment is easy to make, and can be constructed by a
departmental glass blower or by a staff member who is reasonably adept in glassblowing. Making the
equipment does take a little time and plans must be made in advance for its construction. The
experiments in which non-commercially available glassware is desirable are the following:
Experiment 8
Experiment 9
Experiment 15

Measurement of the Atmospheric Pressure – U-tubes
Molar Mass of a Volatile Liquid – Vapor flasks
Vapor Pressure of a Volatile Liquid – Modified pipets

In all cases, we have described in the equipment section how the apparatus can be made. Where it is not
feasible to make the equipment, it is usually possible to use alternate experiments on similar topics; a
vapor flask for Experiment 9 made from commercially available components is described.

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2
In several experiments we use commercial laboratory instruments. These instruments are now
extremely common in all graduate schools and industrial laboratories and in many undergraduate
institutions. We feel that it is highly desirable to introduce students to such apparatus in their first
course. In addition to analytical and top-loading balances, which we use in many of the experiments, the
following experiments include procedures involving the indicated instruments:
Experiment 23
Experiment 25
Experiment 26
Experiment 29
Experiment 32
Experiment 33
Experiment 41
Experiment 42

Determination of an Equilibrium Constant - spectrophotometers
pH and Buffer Properties - pH meters
Determination of a Solubility Product - spectrophotometers
Synthesis of a Coordination Compound - spectrophotometers
Voltaic Cell Measurements - pH meters or high resistance voltmeters
Preparation of Cu(I)Cl - spectrophotometers
Preparation of Aspirin - spectrophotometers
Decomposition of Aspirin - spectrophotometers

The second half of this guide is directed to the laboratory supervisor. For each experiment, we have
included some general comments, an estimate of the time required to complete the experiment and

calculations, complete answers to all Advance Study Assignment questions, and a sample set of
experimental data and calculations.
Although most of the experiments we have included have been tested and found to work quite well,
there may well be problems which arise, in any of the many areas that are involved in the operation of a
laboratory program, which we have not anticipated. The authors would sincerely appreciate any
comments and suggestions from users of the lab manual or this guide. We are eager to help with
troubleshooting where we can.
Wayne Wolsey

Robert Rossi


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3
List of Experiments
Experiment
1 The Densities of Liquids and Solids
2 Resolution of Matter in Pure Substances, I. Paper Chromatography
3 Resolution of Matter into Pure Substances, II. Fractional Crystallization
4 Determination of a Chemical Formula
5 Identification of a Compound by Mass Relationships
6 Properties of Hydrates
7 Analysis of an Unknown Chloride
8 Verifying the Absolute Zero of Temperature—Determination of the Atmospheric Pressure
9 Molar Mass of a Volatile Liquid
10 Analysis of an Aluminum-Zinc Alloy
11 The Atomic Spectrum of Hydrogen
12 The Alkaline Earths and the Halogens—Two Families in the Periodic Table

13 The Geometrical Structure of Molecules—An Experiment Using Molecular Models
14 Heat Effects and Calorimetry
15 The Vapor Pressure and Heat of Vaporization of a Liquid
16 The Structure of Crystals—An Experiment Using Models
17 Classification of Chemical Substances
18 Some Nonmetals and Their Compounds—Preparation and Properties
19 Molar Mass Determination by Depression of the Freezing Point
20 Rates of Chemical Reactions, I. The Iodination of Acetone
21 Rates of Chemical Reactions, II. A Clock Reaction
22 Properties of Systems in Equilibrium—Le Châtelier's Principle
23 Determination of the Equilibrium Constant for a Chemical Reaction
24 The Standardization of a Basic Solution and the Determination of the Molar Mass of an Acid
25 pH Measurements—Buffers and their Properties
26 Determination of the Solubility Product Constant of Ba(IO3)2
27 Relative Stabilities of Complex Ions and Precipitates Prepared from Copper(II)
28 Determination of the Hardness of Water
29 Synthesis and Analysis of a Coordination Compound
30 Determination of Iron by Reaction with Permanganate—A Redox Reaction
31 Determination of an Equivalent Mass by Electrolysis
32 Voltaic Cell Measurements
33 Preparation of Copper(I) Chloride
34 Development of a Scheme for Qualitative Analysis
35 Spot Tests for Some Common Anions
36 Qualitative Analysis of Group I Cations
37 Qualitative Analysis of Group II Cations
38 Qualitative Analysis of Group III Cations
39 Identification of a Pure Ionic Solid
40 The Ten Test Tube Mystery
41 Preparation of Aspirin
42 Rate Studies on the Decomposition of Aspirin

43 Analysis for Vitamin C

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4
EQUIPMENT AND CHEMICAL REAGENT REQUIREMENTS FOR EXPERIMENTS
Note to stockroom personnel:
In stating equipment and chemical reagent needs, we have adhered to the following norms:
I. Laboratory equipment requirements are for a class of 20 students.
II. Suggested reagent container sizes are those we have found convenient for use with lab sections
of 20 students. Typically we use four bottles of each reagent, one per lab bench. Amounts are
usually more than one section of students will use, so that we do not need to refill the bottles
during a lab session, or even (in most cases) during a day of sessions. Following the statement of
the number and kind of container and the reagent, we list in parentheses the amount of that
reagent which we think an average student will use. This should give you a rough guide as to
requirements of chemicals for ordering purposes, as well as for preparation of solutions in
advance.
III. Chemical reagents are listed by both their formula name and their word name. When making
labels for containers, it would probably be best, in this course, to include both the formula name
and the word name, along with the concentration of reagent, if it is given. For example:
18 M H2SO4
or
0.5 M NaOH
conc. sulfuric acid
sodium hydroxide
We have used to good advantage a commercially available unit, which prints the name of the
chemical on 1/2" vinyl tape, which comes in different colors. This makes a neat, chemicalresistant label.
IV. Disposal of used reagents and reaction products must be handled properly. At the end of each
experiment we tell the students what they are to do with the products of the reactions they carried

out. Following the section directed toward laboratory supervisors there is a section on disposal
of the chemical wastes from each experiment. If you follow the procedures we describe, you
will minimize the amount of waste that needs to be picked up by a commercial hazardous waste
disposal firm.
V. At the end of this guide there is a list of all the reagents used in the experiments, including some
of the unknowns, and directions as to how each reagent solution is to be prepared. Chemicals are
listed in alphabetical order by their word names, with chemical formulas of the substances given
in the preparation directions.

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5
VI.

There are several possible sources of the chemicals, glassware, and apparatus needed in
the experiments. Some of the larger supply houses are listed below, with their addresses
and toll-free telephone numbers:
Sigma-Aldrich
PO Box 14508
Saint Louis, MO 63178-4508
1-800-325-3010
www.sigmaaldrich.com
Reagents & Equipment

Alfa Aesar
26 Parkridge Road
Ward Hill, MA 01835-8514
1-800-343-0660
www.alfa.com

Reagents & Pure Metals

Frey Scientific
PO Box 3000
Nashua, NH 03061-3000
1-800-225-3739 [FREY]
www.freyscientific.com
Equipment, K-12 focus

Fischer Scientific
2000 Park Lane Drive, Suite 2
Pittsburgh, PA 15275-1104
1-800-766-7000
www.fishersci.com
Reagents & Equipment

Flinn Scientific
PO Box 219
Batavia, IL 60510-0219
1-800-452-1261
www.flinnsci.com
Reagents & Equipment

Strem Chemicals
7 Mulliken Way
Newburyport, MA 01950-4098
1-800-647-8736
www.strem.com
Reagents & Pure Metals

Cole Palmer
625 East Bunker Court
Vernon Hills, IL 60061-1844
1-800-323-4340
www.coleparmer.com
Equipment & Pure Metals

Sargent Welch Science Education
PO Box 4130
Buffalo, NY 14217-0360
1-800-727-4368
www.sargentwelch.com
Reagents & Equipment
(a subsidiary of VWR)

Ace Glass
PO Box 688
1430 North West Boulevard
Vineland, NJ 08362-0688
1-800-223-4524
www.aceglass.com
Glassware

VWR Scientific Products
800 East Fabyan Parkway
Batavia, IL 60510-1406
1-800-932-5000
www.vwr.com
Reagents & Equipment

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6
EXPERIMENT 1
The Densities of Liquids and Solids
Special equipment needed:
20 25 mL Erlenmeyer flasks with standard taper stoppers for use as pycnometers
Reagent available in laboratory:
4 × 250 mL wash bottles of acetone (10 mL/student)
Sample preparations:
A. Mass of a coin:
Students are to furnish their own coins, but you may want to have some pennies available for
those who need them.
B. Density of a liquid:
The following liquids are suitable as unknowns. A total of 600 mL of organic liquids are
required for 20 students. 30 mL of liquid should be placed in a large, numbered test tube.
For the most part, these liquids can be recovered and re-used in the next laboratory section.
I
ethanol
IV cyclohexane
II
isopropyl alcohol (2-propanol)
V toluene
III
n-heptane
Note: For large classes, using technical grade solvents will cut costs; the chemical quality of
the solvents is not of great importance, provided the actual density is known. Use other
solvents if available, but check for toxicity and carcinogenicity.
C. Density of a metal:

250 grams of each metal should be made available as unknowns. Fifty grams should be
sufficient to constitute the unknown issued to each student. All solid chunks must be small
enough to pass through the neck of the 25 mL Erlenmeyer flask used as the pycnometer. The
metal pieces used should not have any entrapped air bubbles, as these will lead to erroneous
density values. Metals can be recovered, cleaned easily by rinsing with acetone, and allowed
to dry on a paper towel. Prepare one day's unknowns on the previous day, if possible, such
that they have time to dry thoroughly. The following metals are suggested:
A. aluminum shot
E. copper shot
B. bismuth shot
F. nickel shot
C. chromium pieces
G. tin shot
D. cobalt shot
H. zinc shot
Cost per student, not counting recoverable metal and liquid samples: 30¢
Metal samples, approximate cost per 50 g (purchased in ~500 g quantities):
aluminum $4.48
cobalt $22.60
tin $7.80
bismuth $11.00
copper $6.19
titanium* $9.60
chromium $11.50
nickel $9.10
zinc $5.74
zirconium* $59.00
* For very hard metals, purchase wire and cut it. The wire is hard to cut, but this is the easiest way.
Sources of metals: Alfa, Strem, Fisher, and Flinn, among others; prices vary widely. As with the
liquids, the purity is not critical, provided that the metal is nominally pure, rather than an alloy. You

will find that high-purity (>99.9%mass) metals cost appreciably more than the amounts shown above.
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7
EXPERIMENT 2
Resolution of Matter into Pure Substances
I. Paper Chromatography
Special equipment needed:
20 pieces of Whatman #1 filter paper, 19 cm × 11 cm, cut from 57 cm × 46 cm sheets
Whatman #1 circular filter paper, 2" diameter or whatever is convenient, for use in practicing
spotting
20 capillary melting point tubes, Kimax #34500-99 or Corning #9530-1
8 12" rulers or meter sticks; put on lab benches
2 tape dispensers
4 spray bottles which produce a fine spray
Reagents needed in the laboratory:
4 × 500 mL Eluting Solution, made by mixing 500 mL 6 M HCl with 400 mL ethanol and 400 mL
n-butanol (15 mL/student)
Use spray bottles for Staining Reagent (see Directions for Preparing Reagents)
4 × 2 oz dropping bottles of the following solutions (0.5 mL of each/student):
0.1 M AgNO3
0.1 M Co(NO3)2
0.1 M Cu(NO3)2
0.1 M Fe(NO3)3
0.1 M Bi(NO3)3
Preparation of unknowns:
Use two or three drops of the solutions listed below, in micro test tubes:
I AgNO3 - Cu(NO3)2 - Fe(NO3)3
II Co(NO3)2 - Fe(NO3)3 - Bi(NO3)3

III Cu(NO3)2 - Fe(NO3)3 - Bi(NO3)3
IV AgNO3 - Co(NO3)2 - Bi(NO3)3
Cost per student: 25¢

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8
EXPERIMENT 3
Resolution of Matter into Pure Substances
II. Fractional Crystallization
Special equipment needed:
20 Buchner funnels taking 70 mm filter paper in #6 1-hole stoppers
20 250 mL filtering flasks
4 boxes Whatman #1 7 cm diameter filter paper circles
Several aspirators (safety flasks should be installed) or other vacuum source
20 pneumatic troughs or ice cream buckets for ice baths
20 rubber policemen on stirring rods
Ice - crushed, at least 5 lbs.
Reagents needed in the laboratory:
4 × 200 mL dropping bottles 6 M HNO3, nitric acid (2 mL/student)
4 × 200 mL dropping bottles 6 M NH3, ammonia (6 mL/student)
Preparation of standard Cu(NH3)42+ solutions:
Make a copper stock solution by dissolving 4.2 g CuSO4 · 5 H2O in 500 mL water.
Fill a buret with that solution and another buret with deionized water.
Measure out and combine the volumes (in mL) of the copper (Cu) stock solution, water (H2O),
and 6 M NH3 (nitric acid) listed below; put the resulting standards in small test tubes, label as
to concentration as shown below, and arrange in a test tube rack; put 6 mL in each test tube.
%mass CuSO4 · 5 H2O
in recovered KNO3

mL Cu stock sol'n
mL H2O
mL 6 M NH3
5
5
0
5
3
3
2
5
1
1
4
5
0.5
0.5
4.5
5
0.3
0.3
4.7
5
0.1
1 mL 1% sol'n
4
5
0.05
1 mL 0.5% sol'n
4

5
0.03
1 mL 0.3% sol'n
4
5
0.01
1 mL 0.1% sol'n
4
5
It is recommended that these test tubes be prepared in a hood or well-insulated area, and then stoppered
before being made available to the students, so as to minimize ammonia fumes in the laboratory.
It is critical that all test tubes used in this portion of the experiment be of the same diameter.
Preparation of unknowns:
Each student should be given about 20 g of a solid unknown. Prepare in large batches, 500 g or
so. Mix thoroughly before dispensing, grinding the salts if necessary to keep the mixture
homogenous.

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9
Suggested unknown compositions (for 500 g batches):
SiC
KNO3
(~120 mesh/grit)
(purified grade)
I
60 g
400 g
II

80 g
380 g
III
100 g
360 g
IV
120 g
340 g

CuSO4 · 5 H2O
(technical grade)
40 g
40 g
40 g
40 g

Recover and reuse SiC and purified KNO3. Keep in separate containers.
Cost per student: 30¢

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